How did Mark Antony's defeat allow Octavian to become Augustus?

Mark Antony’s defeat was the pivotal event that allowed Octavian to consolidate absolute power and become Augustus, the first Roman emperor.12

Following the dissolution of the Second Triumvirate, Octavian engaged in a sophisticated propaganda war, framing Antony as a man who had abandoned Roman interests to become a Hellenistic king in Alexandria alongside Cleopatra. By declaring war on Cleopatra rather than Antony directly, Octavian unified the Roman West under his leadership.34

The decisive Battle of Actium in 31 BCE resulted in the disintegration of Antony’s forces. After Antony and Cleopatra committed suicide in 30 BCE, Octavian annexed Egypt. The seizure of Cleopatra’s vast treasure provided the financial means for Octavian to pay off his veterans and secure the loyalty of his legions. With his primary rival eliminated and his military and financial position unassailable, Octavian was able to transition the state into the Roman principate, establishing a system of government that granted him absolute control over the Roman world.314